• Congress added Section 129 to the Clean Air Act (CAA) in 1990 specifically to address emissions from solid waste combustion. Section 111 and 129 require EPA to establish new source performance standards (NSPS) for new units, while sections 111(d) and 129 require the Agency to establish emission guidelines for existing units. NSPS are federal regulations that apply to new sources of air pollution. Performance standards do not directly regulate solid waste combustion units, but rather establish requirements for state plans, which are the vehicle by which states implement these standards. The standards do set specific limits on emissions of specific pollutants including dioxin.
• Section 112 of the Clean Air Act Amendments of 1990 lists 2,3,7,8-tetrachlorodibenzo-p -dioxin (TCDD) as a hazardous air pollutant, indicating that it is "known or suspected to cause cancer or other serious health effects such as birth defects or reproductive effects." As a result, the CAAA directs the EPA to identify the sources of 90% of its emissions and to set standards that require companies within a listed source category to sharply reduce their emissions. Industries identified as sources are required to implement maximum achievable control technology (MACT). This reflects the maximum amount of hazardous air pollution reduction that is possible when the availability, current use, costs, benefits, and impacts of emission control technology are considered. Regulations were implemented in 1995 for municipal waste combustors and in 1997 for medical waste incinerators. As a result, a 95% reduction of dioxin emissions has occured from these two sources. In addition, more recent regulations have been placed upon hazardous waste incinerators that are expected to result in a 70% reduction of dioxin and furan emissions. The pulp and paper industry came under regulation in 1998 under implementation of the Pulp Paper and Paperboard "Cluster Rule." This rule requires mills to capture and treat toxic air pollutant emissions, including dioxin, reducing them by nearly 59%.
• Under the combined authorities of the CAA and the Resource Conservation and Recovery Act (RCRA), EPA has recently regulated dioxin emissions from facilities that burn hazardous waste. These include commercial hazardous waste incinerators, some cement kilns, and lightweight aggregate kilns. With completion of these rules, major categories of commercial hazardous waste combustion are under direct regulation for their dioxin emissions.

Water Quality Requirements

• Dioxin releases to water are managed through a combination of risk-based and technology-based tools established under the Clean Water Act (CWA). Using authority of the CWA, EPA published in 1984 ambient water quality criteria for 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Ambient water quality criteria serve as EPA guidance for states in establishing and adopting their own ambient water quality standards. These state standards set a limit on the maximum pollutant concentration allowed for surface waters anywhere within that state and are implemented through discharge limitations contained in National Pollutant Discharge Elimination System (NPDES) permits.
• In 1993, EPA proposed integrated rules for the pulp and paper industry, which included an effluent guideline for dioxin. Effluent guidelines establish limits on facility effluent concentrations based upon application of best available control technology as defined by the CWA. Pulp and paper effluent guidelines were promulgated in 1998 and reduce this industry's dioxin discharges at least 96%. The technology-based effluent guidelines are implemented under the NPDES program along with health-based, state ambient water quality standards. Under the NPDES, each facility must meet the more stringent of these separate performance requirements that are placed upon it.
• To maintain the quality of public drinking water, in 1992 EPA promulgated a maximum contaminant level goal (MCLG, a non-enforceable, voluntary health goal) of zero, and a maximum contaminant level (MCL) of 3x10-8 mg/l for TCDD under the Safe Drinking Water Act (SDWA).
• In addition to these direct regulatory actions under the CWA and SDWA, EPA is working with the states and Army Corps of Engineers to manage dredging and disposal of dioxin-contaminated sediments.

Land Contamination Cleanups

• Cleanup of dioxin-contaminated lands is an important part of the EPA Superfund and RCRA Corrective Action Programs. There are dozens of Superfund sites around the country in which dioxin is one of the chemicals of concern. To prevent future problems like these, EPA has developed, under RCRA authority, Hazardous Waste Identification and Disposal Rules. These rules identify and strictly limit disposal options for wastes formally designated as dioxin-containing waste.
• Dioxin can also be found in low concentrations in wastes applied to the land as fertilizers or soil amendments. These materials include wastewater treatment sludge from pulp and paper plants, sludge from publicly owned wastewater treatment facilities, and dust from activities at cement plants. Under authority of the Toxic Substance Control Act (TSCA), EPA proposed rules to restrict use of dioxin-contaminated pulp and paper sludge. Subsequent promulgation (1998) of pulp and paper effluent guidelines should effectively reduce dioxin concentration in this sludge to such an extent that promulgation of the TSCA sludge rule is no longer needed. In the interim, the paper industry has participated in a voluntary program to limit dioxin concentration to land-applied pulp and paper sludge.
• In 1999, EPA proposed but never finalized regulations limiting the dioxin content of cement kiln dust from cement plants and sludge from publicly owned sewage treatment facilities when these by-product materials are used as soil additives.

Product Quality Requirements

• Authorization under the Federal Insecticide Fungicide and Rodenticide Act (FIFRA), and under TSCA, can be used to control or eliminate use of certain industrial chemical products. Registration of the herbicide 2,4,5-T was canceled because of concern for dioxin. Similarly, most of uses of the wood preservative pentachlorophenol have been eliminated, in part because of concern for dioxin.
• The Toxic Substance Program, through voluntary industry agreements, has restricted levels of dioxin found in the industrial chemical chloranil. Chloranil is used in the manufacture of certain pigments and tires. Additionally, the TSCA New Chemicals Program, in cooperation with industry, has effectively prevented the manufacture of any new chemicals significantly contaminated with dioxin.

Toxics Release Inventory

• EPA's Toxics Release Inventory was established in 1986 to track information on 650 chemical substances manufactured, processed, or used by U.S. production facilities each year. Dioxin was added to the TRI for reporting purposes beginning in the year 2000. As a result, facilities must report releases of dioxin to the environment if it is created, processed, or otherwise used in amounts of 0.1 gram per year or more.

Source: www.bio.psu.edu/Courses/Spr2003/biol415/web_projects/dioxin/dioxinwebpage.htm, www.epa.gov/ncea/pdfs/dioxin/factsheets/dioxin_regs.pdf, www.dioxinfacts.org/questions_answers/index.html, and www.epa.gov/ttn/atw/129/gil2.html